Thy Flesh Consumed DOOM3 version is just what it says, a return to yesterday...using todays tools.
Singleplayer map, playtime ~1.30 - ~3.30 hour, its a big one, you need some time, the difficulty is hard.
Zsecs will generally act smarter, they will try to retreat after throwing grenades. They will seek cover at certain distances. If near to the player, they will try to approach you for an instant kill.
This is the newest version of Tin Man Squad, a modification for DOOM 3 that provides AI controlled allies to help you along your trip to hell.